Monday was one of the most beautiful weather-days in recent memory and, fittingly, autumn will officially arrive tonight at 10:30pm. Temperatures on Monday reached only into the upper 60’s (lower 70’s in some spots) and the low humidity kept things very comfortable. There was even a bit of a chill in the air at times, as a dry west-northwesterly breeze blew during the afternoon. Autumn will arrive officially tonight just shortly after 10:30pm Eastern.
Sunset tonight will be due west — as the autumnal equinox occurs. Tonight, the sun can be seen a “zenith” before its rays shift into the southern hemisphere for the rest of the year. That means that starting tomorrow, until the middle of winter, the sun will continue to set farther and farther to the south on the horizon. And yes, it also means we’ll be losing much more daylight each day moving forward. In fact, by this time next month, we will have lost a full two hours of daylight at a pace of 2 minutes and 40 seconds lost per day.
The weather this week will play in-tune to the transition to autumn. Temperatures through the middle and end of the upcoming week will reach into the upper 60’s and lower 70’s during the day, with overnight temperatures falling into the 40’s and 50s especially in the suburbs where things may get even cooler.
The only potential wrench in a weekly forecast dominated by high pressure and mid level ridging may come on Thursday. Forecast models have honed in on the potential for a mid level disturbance to spawn a coastal storm from Wednesday Night into Thursday, developing near the Mid-Atlantic coast. Some models even bring a fairly significant amount of precipitation into our area as the surface low tucks near the shore.
There are a few potential problems with this setup. First, the high pressure to the north which all models indicate will be moderately strong at that time and pressing southward. This could effectively suppress the storm to the south and east of our area, negating any potential effects. Alternatively, it could strengthen the gradient between the high pressure and developing coastal storm, resulting in a strengthening onshore fetch and some wind/rain. Second, the warm ocean temperatures off the coast — which could act as some additional fuel for the developing storm system.
Ultimately, we’ll have to wait another day or so until forecast models can get a better idea as to the track and intensity of this coastal storm. Currently, our forecast calls for a glancing blow with an increasing chance of showers from Wednesday Night into Thursday, but no period of prolonged rain. We’re carefully monitoring model trends and will update our forecast as the storm draws near.
Meanwhile, the gorgeous fall weather will continue before (And after) any potential storm. In fact, above normal temperatures may become a viable forecast by the upcoming weekend. Fall foliage, meanwhile, is beginning to get into swing in New England. The latest foliage report shows increasing color for our neighbors to the north.
These colors typically spread south rather rapidly over the next few weeks. The greens which currently dominate our areas foliage will begin to fade and turn bright — before fading finally for the winter. We’ll be anxiously awaiting the barrage of beautiful fall-foliage pictures from around the area.